PROBLEM TO BE SOLVED: To provide a method of manufacturing a radiation detection unit capable of improving position accuracy of each radiation detection module and reducing an interval between the radiation detection modules.SOLUTION: A method of manufacturing a radiation detection unit includes: a first process in which the side part of a first radiation detection module 2a is abutted against a first protrusion MP； a second process in which a second radiation detection module 2b is arranged in a region from which the first protrusion MP is removed after the first process and the side part of the second radiation detection module 2b is abutted against a second protrusion MP； and a third process in which a fitting part 86a of the first radiation detection module 2a and a fitting part 86a of the second radiation detection module 2b are made to face a frame 4 and separated from the frame 4, and the first radiation detection module 2a and the second radiation detection module 2b are fitted to the frame 4.【課題】各放射線検出モジュールの位置精度を向上できると共に、放射線検出モジュール同士の間の間隔を低減できる放射線検出ユニットの製造方法を提供すること。【解決手段】第１工程では、第１突起ＭＰに第１放射線検出モジュール２ａの側部を突き当て、第２工程では、第１工程の後に、第１突起ＭＰが取り外された領域内に第２放射線検出モジュール２ｂを配置すると共に、第２突起ＭＰに第２放射線検出モジュール２ｂの側部を突き当て、第３工程では、第１放射線検出モジュール２ａの取付部８６ａ、及び、第２放射線検出モジュール２ｂの取付部８６ａのそれぞれを、フレーム４と対向させると共にフレーム４から離間させて、第１放射線検出モジュール２ａ及び第２放射線検出モジュール２ｂのそれぞれをフレーム４に取付ける。【選択図】図７
